Thermoplastic molding compound comprising a blend of isotactic polybutenes

ABSTRACT

A mixture of (a) 10-95% by weight of a highly isotactic polybutene-1 having an RSV value of 1.7 - 4.5 dl./g., a density of 0.913 - 0.920 g.cm3, a yield stress of 190-240 kp./cm2, and an ether-soluble content of 1-15%, and (b) 90-5% by weight of a substantially isotactic polybutene-1 having an RSV value of 1.2 4.5 dl./g., a density of 0.890 - 0.910 g./cm3, a yield stress of 60-150 kp./cm2, a tensile strength at rupture of 160-380 kp./cm2, an ultimate elongation of 300-600%, and an ether-soluble content of 10-30%, is useful as a thermoplastic molding composition, especially for forming films having good transparency and tear transmission resistance in both directions.

United States atent [191 Frese et al.

[451 July 8,1975

[75] Inventors: Albert Frese; Otto Hahmann; Horst Denzel, all of Marl, Germany [73] Assignee: Chemische Werke Huels Aktiengesellschaft, Marl, Germany 22 Filed: Oct. 31, 1973 21 App]. No.: 411,394

[30] Foreign Application Priority Data Nov. 4, 1972 Germany 2254128 [52] US. Cl. 260/897 A; 260/937; 260/94.9 B [51] Int. Cl. C081 29/12 [58] Field of Search 260/897 A, 93.7, 94.9 B

[56] References Cited UNITED STATES PATENTS 2,882,263 4/1959 Natta 260/897 A 3,356,765 12/1967 Musso 260/897 A 3,362,940 1/1968 Edwards 260/937 5/1968 Jones 260/949 B 3,634,551 1/1972 Stancell 260/897 A FOREIGN PATENTS OR APPLICATIONS 1,915,061 11/1970 Germany 1,184,742 10/1957 France Primary ExaminerJhn C. Bleutge Assistant Examiner-C. J Seccuro Attorney, Agent, or FirmMillen, Raptes & White 7] ABSTRACT A mixture of (a) -95% by weight of a highly isotactic polybutene-l having an RSV value of 1.7 4.5 dl./g., a density of 0.913 0.920 gem a yield stress of 190-240 kp./cm and an ether-soluble content of 1l5%, and (b) 5% by weight of a substantially isotactic polybutene-l having an RSV value of 1.2 4.5 dl./g., a density of 0.890 0.910 g./cm a yield stress of 60l50 kp./cm a tensile strength at rupture of 380 kp./cm an ultimate elongation of 300-600%, and an ether-soluble content of l030%, is useful as a thermoplastic molding composition, especially for forming films having good transparency and tear transmission resistance in both directions.

9 Claims, No Drawings THERMOPLASTIC MOLDING COMPOUND COMPRISING A BLEND OF ISOTACTIC POLYBUTENES BACKGROUND OF THE INVENTION This invention relates to isotactic polybutene-l thermoplastic molding compositions.

Films of highly isotactic polybutene-l have the great disadvantage that they exhibit a low transparency and fluctuating strength values, especially very differing film tear strength, i.e., tear resistance, in the longitudinal and transverse directions. For this reason, such highly isotactic polybutene-l films are unsuitable for many fields of application.

By increasing the atactic proportion, the transparency of the polybutene-l films can be improved only slightly. For example, if during processing that atactic proportion is not separated together with the solvent but rather left in the product by precipitation with alcohol or by evaporation of the solvent, a polybutene-l is obtained from which, even with ether-soluble proportions of 10-20%, films are produced having only a slight improvement in transparency. The film tear strength is not improved as compared to the highly isotactic polybutene-l and is very different in the longitudinal and transverse directions, e.g., 24.8 kp./mm. 1ongitudinally and only 0.89 kp./mm. transversely.

Under certain polymerization conditions described in the application of Albert Frese, S. N. 400899, filed Sept. 26, 1973, it is possible to produce by solution polymerization of butene-l employing a special catalyst system, a polybutene-l which is suitable for film manufacture. Although this material is suitable for film production, one must accept lowered yield stress values and a reduction of Vicat temperature.

Therefore, it is an object of this invention to provide polybutene-l compositions which form transparent films which have improved yield stress values and a higher Vicat temperature.

SUMMARY OF THE INVENTION According to this invention, there is provided a polybutene-l mixture of a. 10-95% by weight of a highly isotactic polybutene- I having an RSV value of 1.7 4.5 dl./g., a density of 0.913 0.920 g./cm a yield stress value of 190-240 kp./cm and an ether-soluble content of l-l5%; and

b. 90-5% by weight of a substantially isotactic polybutene-l having an RSV value of 1.2 4.5 dl./g., a density of 0.890 0.910 g./cm a yield stress value of 60-150 kp./cm a tensile strength at rupture of 160-380 kp./cm an ultimate elongation value of 300-600%, and an ether-soluble content of -30%.

In a preferred aspect, there is provided film formed of such a polybutene-l mixture.

DETAILED DISCUSSION 0.913-0920 g/cm, preferably 0.915-0918 g/cm 1 preferably 1.5 7.5

density ether-soluble content yield stress tensile strength at rupture ether soluble content yield stress 60 150 kp/cm preferably kp/cm tensile strength at rupture 380 kp/cm preferably 200-350 kp/cm ultimate elongation 300 600 preferably 350 550 Vicat temperature 7 4 110C, preferably 100 107C The mixtures of this invention preferably consist of 40-70% of the highly isotactic polybutene-l and 60-30% of the substantially isotactic polybutenel of lower crystallinity.

An example of a suitable highly isotactic polybutene- 1 is a polybutene-l having an RSV value of 1.7 4.5 d1./g., i.e., a molecular weight of 620,000 2,1 12,000, preferably of 2.0 3.5 dl./g., i.e., a molecular weight of 766,000 1,554,000, a density of 0.9 1 3 0.920 g./cm and an ether-soluble proportion of 1-15%, preferably 1.5 7.5%. Polymers having higher RSV values have lower ether-soluble proportions and those with lower RSV values have higher ether-soluble proportions. Such a highly isotactic polybutene-l has a yield stress value of -240 kp./cm In addition to butene-l homopolymers, butene-l copolymers having a comonomer content of up to about 5% can also be employed. Preferred comonomers are C C a-olefins, e. g., propene, hexene-l, dodecene-l.

Such a highly isotactic polybutene-l can be produced by polymerizing butene-l optionally in the presence of up to about 5% of one or more comonomers, at a temperature of 20 to +50 C., preferably 2535 C., employing a mixed catalyst of titanium trichloride, on the one hand, and a dialkylaluminum chloride, on the other hand. Suitable as the butene-l is high-percentage butene-l, as well as C.,-cuts containing butene-l. As the titanium trichloride, a product such as TiCl 0.2-0.6 A1Cl is preferably employed, as it is obtained by the reduction of titanium tetrachloride with aluminum or with alkylaluminum compounds, especially ethylaluminum sesquichloride. Diethylaluminum chloride is the preferred dialkylaluminum chloride. The polymerization is preferably accomplished in the liquid phase in suspension without added diluent.

The substantially isotactic polybutene-l of a lower crystallinity has RSV values of 1.2 4.5 dl./g., preferably 2.0 3.5 dl./g. This corresponds to a molecular weight of 394,000 2,112,000, preferably 766,000 1,554,000. These products have a density of 0.89 0.91 g./cm preferably 0.895 0.908 g./cm ethersoluble proportions of 10-30%, preferably 15-25%, yield stress values of 60-150 kp./cm preferably 80-120 kp./cm tensile strength at rupture values of 160-380 kp./cm and ultimate elongation values of 300-600%. In addition to butene-l homopolymers, butene-l copolymers having a proportion of comonomer of up to about 15%, preferred comonomers are (jg-C14 a-olefins, e.g., propene, hexene-l, dodecene-l.

Such a substantially isotactic polybutene-l is obtained by polymerizing butene- 1 optionally in the presence of up to 15% of one or more comonomers, at a temperature of 55120 C., preferably 65-100 C.

employing a mixed catalyst of titanium trichloride, on the one hand, and an alkylaluminum compound, on the other hand. A suitable butene-l is high-percentage butene-l, e.g., 95 99%, as well as C, cuts containing, e.g., 40 60% butene-l. A preferred titanium trichloride is TiCl 0.2 0.6 AlCl as it is obtained by the reduction of titanium tetrachloride with aluminum or an alkylaluminum compound, preferably ethylaluminum sesquichloride. Suitable alkylaluminum compounds are trialkylaluminum compounds and aluminum dialkyl chlorides, preferably diethylaluminum chloride. The polymerization is preferably conducted in the liquid phase in solution without the addition of a further solvent.

1 4 a more'favorable stress crack resistance. With special stabilization, this material is especially suitable for the manufacture of degradable mulching films.

Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The following preferred specific embodiments are, therefore, to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever.

EXAMPLE 1 a. A highly isotactic polybutene-l (Product A density 0.9173, ether-soluble proportion 6%) is produced Surprisingly, the mixtures exhibit more favorable val- 15 y the Polymerization of 36 Parts y Weight of butane-l 0 ues with respect to the Vicat temperature than could be Strength) at temperatures of 25 a Partlal predicted from the mixture ratio, as shown in Table I, y g Pressure of L6 atmospheres a total P below. sure of 3.5 4.0 atmospheres gauge with the aid of a TABLE 1 Vicat A Yield Stress Density C. kp./cm g./cm"

Highly isotactic polybutene-l (A 122 231 0.9173 Substantially isotactic polybutene-l (8,) 105 123 0.9050 Mixture 60% A and 40% B l 19 188 0.9085 Mixture 50% A and 50% B 1 15 175 0.9079 Highly isotactic polybutene-l (A 120 217 0.9160 Substantially isotactic polybutene-l (B 74 72 0.8973 Mixture 95% A and 5% B 119 232 0.9157 Mixture 90% A and B 119 230 0.9150 A, Mixture 85% A and B 118 216 0.9152 Mixture 70% A and B 1 13 190 0.9108 Mixture 50% A and 50% B 106 148 0.9034

The yield stress values are, in part, also higher than would be expected from the mixture ratio, whereas the density of the mixtures is partially lower than corresponds to the mixture ratio, especially in case of mixture ratios of 60 to 50 50. The tensile strength at rupture and ultimate elongation values are likewise largely more favorable than would be expected from the mixture ratio.

When adding substantially isotactic polybutene-l with low yield stress values of, for example, only 72 kp./cm as a small amount as 5% can lead to improved property values and especially to an improvement of the transparency of the film. However, even in the case of these mixtures, larger amounts of about 30-40% are preferred. in case of products having yield stress values of 80-120 kp./cm mixtures containing 40-50% of the substantially isotactic polybutene-l are preferred, and in case of products having yield stress values of 120-150 kp./cm 5070% content is preferred.

The polybutene-l blend of this invention is excellently suitable for being processed into films, which films are heat sealable.

An advantage of these films formed from these polybutene-l mixtures is good dimensional stability at high temperatures. The Vicat temperature is only slightly lowered, compared to the highly isotactic polybutene-l. Moreover, the films have excellent transparency, good stretchability, and improved film tear resistance, compared to films of highly isotactic polybutene-l. As contrasted to high-pressure polyethylene, this butene-l film material has the advantage, in addition to an improved thermal dimensional stability, of exhibiting better cold flow, higher penetration, and

mixed catalyst of 0.013 part by. weight of a titanium trichloride (commercial.aluminum-reduced titanium trichloride TiCl 0.33 AlCl and'0;O15 part by weight of diethylaluminum monoch1oride.-,-

b. A substantially isotactic polybutene-J Product B density 0.9050, ether-soluble proportion 18.5%) is produced by the polymerization of 36 parts by weight of butene-l (98% purity) at a temperature of C. and under a pressure of 151 2 atmospheres gauge with the aid of a mixed catalystof 0.0073 part by weight of diethylaluminum monochloride and 0.0066 part by weight of a TiCl 0.5 AlCl catalyst prepared by the dropwise addition of one mole of titanium tetrachloride (100%) at 5 C. Within 6 hours with 1.4 moles of a 20% strength hexane solution, cooled to '5 C., of ethylaluminum sesquichloride (molecular weight 123.7), with a post reaction of 15 hours at 0 C. to +10 C., a tempering step at C. for 6 hours, and a subsequent separation and granulation of the catalyst precipitate.

c. The highly isotactic (Product A and the substantially isotactic (Product 13,) polybutene-l are mixed in weight ratios of 60:40 and 50:50 and then granulated. For comparison purposes, Product A and Product B were also granulated individually. The thus-obtained granulated products were made into blown films in a blown-film manufacturing device. All products can be readily processed. However, the films produced from Product A have a poor transparency and an insufficient tear resistance. The films produced from Product B and especially the mixture of Products A and B exhibit very good transparency. The four thus-obtained granulated products and the films produced therefrom have the properties given in Tables 11 and Ill.

TABLE 11 A, B, Mixturc Mixture 60% A,, 50% A,, Polymer Properties 40% B, 50% B,

RSV dl./g. 1.95 2.5 2.2 2.1 IQOIZJG g./ mm 2.8 1.0 1.6 1.7 Ml g./10 mm 13.6 7.2 8.0 8.2 Density gJCm- 0.9173 0.9050 0.9085 0.9079 Yield stress 1 p./cm 231 123 188 175 Tensile strength at rupture kpJcm 357 269 345 316 Ultimate elongation 7a 327 393 370 347 Vicat A C. 122 105 119 115 TABLE 111 A, B, Mixture Mixture 60% A,, 50% A, Film Properties 40% B, 50% B,

Yield stress, kp./ :m longitudinal 222 160 187 190 transverse 222 107 213 162 Elongation at yield stress, 7: longitudinal 16 16 16 16 transverse 16 16 16 16 Tensile strength at rupture. longitudinal 444 387 413 419 kp./cm" transverse 233 267 333 276 Ultimate elongation. 7t longitudinal 138 190 176 238 208 302 302 274 Resistance Tear. longitudinal 2.4 14.0 10.5 1 1.2 kp./mm. transverse 4.4 26.8 16.2 18.3 Tensile impact test. kp.cm./cm longitudinal 639 1065 1 104 l 155 transverse 305 1 183 802 704 Tensile notch impact test. longitudinal 132 232 168 189 kp.cm/cm' transverse 124 225 162 177 Penetration, kp. 20.1 27.2 23.6 24.8 Welding factor 0.4 0.5 0.6 0.5

EXAMPLE 2 weight of a C -cut consisting of 53% strength butene-l and remainder butene-2 and butane under a partial hya. A highly isotactic polybutene-l (Product A dendrogen pressure of -0.2 atmosphere and a total pressure sity 0.9160, 2% ether-soluble proportion) is produced of 9-7 atmospheres gauge with the aid of a mixed cataby the polymerization at 35 C., of 36 parts by weight lyst of 0.015 part by weight of diethylaluminum monoof a C -cut consisting of 53% butene-l and the remainchloride and 0.013 part by weight of a TiCl 0.5 A-lCl der butene-2 and butane, under a partial hydrogen catalyst, produced by the reduction of 1 mole of TiCl, pressure of 0.8 atmospheres and a total pressure of 4.0 (100%) at 0 C. by the dropwise addition thereof within 3.5 atmospheres gauge with the aid of a mixed cata- 40 6 hours to 1.4 moles of A1(C H Cl, (20% solution lyst of 0.025 part by weight of a titanium trichloride in hexane), with a post reaction time of 6 hours at 0 (commercial aluminum-reduced titanium trichloride C. to 10 C. and subsequent separation of the catalyst TiCl 0.33 A1Cl and 0.03 part'by weight of diethylalprecipitate. uminum monochloride. c. Product A Product B and mixtures thereof in the b. A substantially isotactic polybutene-l (Product B ratios shown in Table IV are granulated. The thusdensity 0.8973, 17.6% ether-soluble proportion, is proobtained granulated material and the films produced duced by the polymerization at C. of 36 parts by therefrom have the values given in Tables 1V and V.

TABLE IV Values for the A B A 90% A. 85% A 70% A. 50% A. Granulated Material 5% B2 10% B2 15% B2 30% B; 50% B2 RSV dl./g. 3.0 2.8 2.9 2.9 2.9 2.8 2.8 1711 g./10 min. 0.5 1.2 1.6 1.5 1.8 2.0 2.3 g./l0 min. 3.0 8.4 8.1 8.0 10.0 12.3 14.1 Density gJtIm 0.9160 0.8973 0.9157 0.9150 0.9152 0.9108 0.9034 Yield stress k ./cm 217 72 232 230 216 190 148 Tensile strength at rupture kp./cm 350 183 376 374 366 324 293 Ultimate elongation 270 530 293 313 320 313 377 VicatA C. 74 119 119 118 113 106 TABLE V Film Properties A2 13 95% A2 90% A2 85% A2 70% A2 50% A2 5% B2 10% B2 15% B 30% B2 50% B2 Yield stress. kp./cm longitudinal 134 142 195 225 156 transverse 200 l 12 210 205 170 125 Elongation at yield longitudinal l6 14 16 20 18 18 stress, transverse "1'6 18 16 21 19 26 26 Tensile strength at longitudinal 250 400 560 485 610 455 460 TABLE V Continued Film Properties A B 95% A 90% A 85% A 70% A 50% A 5% B B B B B rupture, kp./cm transverse 270 240 385 335 320 370 290 Ultimate elongation. 7c longitudinal 168 230 265 265 265 210 transverse 135 406 330 330 310 350 330 Resistance longitudinal 2.4 12.1 8.6 9.1 9.4 11.9 14.5 Tear, kp./mm. transverse 1.2 20.3 15.9 16.2 14.0 24.8 28.6 Tensile impact test, longitudinal l 1020 2010 975 2215 2135 1065 kp.cm./cm transverse 306 960 l 1 905 1 145 945 Tensile notch impact longitudinal 126 210 280 230 550 290 450 test, kp.cm./em" transverse l 12 186 235 200 210 240 220 Penetration, kp. 20.4 26.5 20.7 21.4 22.3 23.1 24.6 0.3-0.4 0.5 0.4 0.5 0.5 0.6 0.6

Welding factor The preceding examples can be repeated with similar success by substituting the generically or specificallly described reactants and/or operating conditions of this invention for those used in the preceding examples.

From the foregoing description, one skilled in the artcan easily ascertain the essential characteristics of this invention, and without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.

What is claimed is:

1. An isotactic polybutene-l mixture suitable for processing into heat scalable films with good dimensional stability at high temperatures, good transparency and tear transmission resistance in both directions, consisting essentially of:

a. 10-95% by weight of a highly isotactic polybutene- 1 having an RSV value of 1.7-415 dl/g., a density of 0913-0920 g./cm an ether-soluble content of l15%, a yield stress of 190-240 kp/cm a tensile strength at rupture of 200-400 kp/cm an ultimate elongation of 200-400% and a Vicat temperature of 1 l5124 C.; and correspondingly b. 905% by weight of a substantially isotactic polybutene-l having an RSV value of 1.2-4.5 dl/g., a density of 0890-0910 g./cm an ether-soluble content of l030%, a yield stress of 60-150 kp/cm a tensile strength at rupture of -380 kp/cm an ultimate elongation of 300-600% and a Vicat temperature of 74100 C.

2. An isotactic polybutene-l mixture according to claim 1, wherein: 9

a. said highly isotactic polybutene-l has an RSV value of 2.0-3.5 dl.g., a density of 0.9150.9l8

g/cm an ether-soluble content of l.5-7.5%, a yield stress of 200-230 kplcm a tensile strength at rupture of 300-350 kp/cm an ultimate elongation of 250350% and a Vicat temperature of l20l22 C; and

b. said substantially isotactic polybutene-l has an RSV value of 2.0-3.5 dl/g., a density of 0895-0908 g/cm an ether soluble content of l525%, a yield stress of 80-120 Kp/cm a tensile strength at rupture of 200-350 kp/cm an ultimate elongation of 350-500% and a Vicat temperature of 100-107 C.

3. An isotactic polybutene-l mixture according to claim 2, comprising 40-70% of component (a) and correspondingly 6030% of component (b).

4. An isotactic polybutene-l mixture according to claim 3, comprising -5060% of component (a) and correspondingly 50-40% of component (b).

5. A film formed of an isotactic polybutene-l mixture according to claim 4. I 7 I 6. The mixture according to claim 1 of- 40-70% of (a) a and 60-30% of (b).

7. The mixture according to claim 1 wherein the highly isotactic polybutene-l has an RSV value of 2.0

..- 3.5 dl./g. and an ether soluble portion of 1,5 7.5%.

ing to claim 6. 

1. AN ISOTACTIC POLYBUTENE-1 MIXTURE SUITABLE FOR PROCESSING INTO HEAT SEALABLE FILMS WITH GOOD DIMENSIONAL STABILITY AT HIGH TEMPRATURES, GOOD TRANSPARENCY AND TEAR TRANSMISSION RESISTANCE IN BOTH DIRECTIONS, CONSISTING ESSENTIALLY OF A. 10-95% BY WEIGHT OF A HIGHLY ISOTACTIC POLYBUTENE-1 HAVING AN RSV VALUE OF 1.7-4.5 DL/G., A DENSITY OF 0.913-0.920 G./CM3, AN ETHER-SOLUBLE CONTENT OF 1-15%, A YIELD STRESS OF 190-240 KP/CM2, A TENSILE STRENGTH AT RUPTURE OF 200-400 KP/CM2, AN ULTIMATE ELONGATED OF 200-400% AND A VICATE TEMPRATURE OF 115*-124*C., AND CORRESPONDINGLY B. 90-5% BY WEIGHT OF A SUBSTANTIALLY ISOTACTIC POLYBUTENE-1 HAVING AN RSV VALUE OF 1.2-4.5 DL/G., A DENSITY OF 0.890-0.910 G./CM3, AN THER-SOLUBLE CONTENT OF 10-30%, A YIELD STRESS OF 60-150 DP/CM2, A TENSILE STRENGTH AT REPTURE OF 160-380 DP/CM2, AN ULTIMATE ELONGATION OF 300-600% AND A VICAT TEMPRATURE OF 74*-100*C.
 2. An isotactic polybutene-1 mixture according to claim 1, wherein: a. said highly isotactic polybutene-1 has an RSV value of 2.0-3.5 dl.g., a density of 0.915-0.918 g/cm3, an ether-soluble content of 1.5-7.5%, a yield stress of 200-230 kp/cm2, a tensile strength at rupture of 300-350 kp/cm2, an ultimate elongation of 250-350% and A Vicat temperature of 120*-122* C; and b. said substantially isotactic polybutene-1 has an RSV value of 2.0-3.5 dl/g., a density of 0.895-0.908 g/cm3, an ether soluble content of 15-25%, a yield stress of 80-120 Kp/cm2, a tensile strength at rupture of 200-350 kp/cm2, an ultimate elongation of 350-500% and a Vicat temperature of 100*-107* C.
 3. An isotactic polybutene-1 mixture according to claim 2, comprising 40-70% of component (a) and correspondingly 60-30% of component (b).
 4. An isotactic polybutene-1 mixture according to claim 3, comprising 50-60% of component (a) and correspondingly 50-40% of component (b).
 5. A film formed of an isotactic polybutene-1 mixture according to claim
 4. 6. The mixture according to claim 1 of 40-70% of (a) and 60-30% of (b).
 7. The mixture according to claim 1 wherein the highly isotactic polybutene-1 has an RSV value of 2.0 - 3.5 dl./g. and an ether soluble portion of 1.5 - 7.5%.
 8. The mixture according to claim 1 wherein the substantially isotactic polybutene-1 has an RSV value of 2.0-3.5 dl./g., a density of 0.895 - 0.908 g./cm3, a yield stress value of 80-120 kp./cm2 and an ether soluble content of 15-25%.
 9. A film formed of a polybutene-1 mixture according to claim
 6. 